SLAC-PUB-7870QCD Phenomena and the Light-Cone Wavefunctions of Hadrons

Abstract

Light-cone Fock-state wavefunctions encode the properties of a hadron
in terms of its fundamental quark and gluon degrees of freedom. A
recent experiment at Fermilab, E791, demonstrates that the color
coherence and shape of light-cone wavefunctions in longitudinal
momentum fraction can be directly measured by the high energy
diffractive jet dissociation of hadrons on nuclei. Given the proton's
light-cone wavefunctions, one can compute not only the quark and gluon
distributions measured in deep inelastic lepton-proton scattering, but
also the multi-parton correlations which control the distribution of
particles in the proton fragmentation region and dynamical higher
twist effects. First-principle predictions can be made for structure
functions at small and large light-cone momentum fraction
x. Light-cone wavefunctions also provide a systematic framework
for evaluating exclusive hadronic matrix elements, including timelike
heavy hadron decay amplitudes and form factors. In principle,
light-cone wavefunctions can be computed in nonperturbative QCD by
diagonalizing the light-cone Hamiltonian using the DLCQ method, as in
dimensionally reduced collinear QCD.